管理措施对三江源区"黑土滩"土壤肥力及土壤酶活性的影响

对三江源区典型退化草地“黑土滩”采取施肥及种植垂穗披碱草的恢复措施,结果表明,土壤中的全氮与有机质的相关性显著,全磷与有机质的相关性较明显,变化趋势相一致。短期的恢复措施造成了恢复样地20~30 cm土壤层中有机质、全氮和全磷含量的下降,长期的恢复措施使恢复样地中的这3种营养物质的含量得到了上升;人工种植措施使土壤中的全钾含量显著下降(P<0.05)。此外,速效养分的变化不一致,其中速效氮的含量表现为先降低后升高,速效磷和速效钾的含量变化表现出升高趋势。植被恢复对土壤脲酶活性有促进作用,但蔗糖酶活性没表现出规律性变化;这2种酶的活性与速效养分的含量表现出较强的正相关,而与有机质和全价养分的含量相关性不显著。     

冬小麦精准追肥机专家决策系统

为了实现小麦生长过程中的实时变量追肥,研究了光谱数据处理策略及目标追肥量的计算模型,开发了基于近地光谱探测技术的实时变量追肥专家决策系统,结合小麦冠层归一化植被指数(NDVI)、追肥机实际行进速度和肥料反馈量,双通道独立控制施肥机构的转速和开度,从而实时调整追肥量,实现精准变量追肥。试验结果表明,专家决策系统的控制精度达到90%以上,可以满足精准追肥的要求;拔节期,变量追肥比定量均匀施肥增施氮肥28 kg/hm2左右;变量施肥有利于改善小麦群体结构,降低产量差异性。     

军事医学科学院2006-2009年在CMCI收录期刊上发表的论文及其被引情况

对军事医学科学院2006-2009年在CMCI收录期刊发表的论文及其被引情况进行了分析,以期对该院未来的学科发展有所帮助。     

The use of a new portable erosion measuring device for assessing the erodibility of the surface layers of flood embankments

When a river overtops its flood banks, water running down the landward side of the bank can rapidly erode the soil surface and scour the bank, sometimes leading to breaches and collapse. A covering of living vegetation, particularly grass, can reduce this risk of water erosion. As part of a project to assess the effectiveness of different management regimes on bank vegetation cover, direct measurements were required of the erodibility of the soil surface. A portable erosion measurement device (EMD) was developed by LAB Coastal with the support of the Environment Agency. This could direct water flowing at known velocities across areas of the flood banks, and it was used to test directly the erosion resistance of vegetated grass banks at three sites. The EMD gave a direct measure of the erodibility of a small sample of flood bank. While measurements of soil strength and assessments of vegetation cover were useful, they did not always correctly characterize the stability of the bank surface as measured directly by the EMD. The EMD and its use are described and the results obtained are discussed. The results indicate that flood banks need to be mown at least once a year to make them less vulnerable to erosion.     

Soil conservation on road embankments using palm‐mat geotextiles: field studies in Lithuania

The application of geotextile mats constructed from the palm leaves of Borassus aethiopum (Borassus) and Mauritia flexuosa (Buriti) was investigated in field experiments. The use of geotextiles caused improved soil moisture storage during dry summer periods on a steep (21–25°) roadside slope in Lithuania. The enhanced soil moisture under the Borassus and Buriti mats encouraged better root development of perennial grasses, increased the number and weight of earthworms and increased the dry biomass of perennial grasses by 50.5 and 18.2%, respectively, compared with a grassland control. The mean rate of water erosion from bare soil during the study period from 17/04/2007 to 11/12/2008 was 33.21 Mg/ha. The cover of palm‐mat geotextiles decreased soil losses from bare fallow soil by 94.8–91.1%. An erosion rate of 0.85 Mg/ha over this 21‐month period was measured on the slope under perennial grasses without geotextile cover. Application of geotextile cover on perennial grasses completely prevented soil erosion by water. Therefore, use of geotextiles has clear soil and water conservation benefits on industrial slopes susceptible to erosion. The use of geotextiles has multiple benefits including soil conservation, the improvement of plant growth conditions and the encouragement of earthworm populations.     

浅谈额济纳旗狼心山水利枢纽工程的利弊

由于全球气候变化而导致的气候干旱正严重影响着我国的西部地区,黑河流域上游过度的农业开发和城市用水的快速增加,导致下游的额济纳绿洲干旱缺水严重,为了解决这个问题,修建了狼心山水利枢纽工程。此工程虽然部分的解决了干旱缺水的问题、但也存在着弊端。如何解决这一工程缺陷,是今后研究的问题,文章提出了解决的方法供参考。     

塔克拉玛干沙漠公路沿线植被及特点

本文以塔克拉玛干浙江省公路为主线，调查由沙漠北缘至腹地自然概况，植物组成及分布特点，植被类型等，结果表明，塔克拉玛干沙漠公路沿线植物组成非常贫乏，仅１８种；生态学特性则以中生，耐盐的高位芽植物占主导地位；大多数植物以根蘖为主要繁殖形式；植被类型简单、隐域性盐化草甸植被占有一定的地位。     

对退耕还林还草有关问题的进一步思考

阐述了“一退双还”政策措施提出的意义和实施情况,提出应进一步明确“一退双还”的目的,从思想和政策上解决重林木轻草灌的倾向,力戒形式主义和表面文章、讲求实绩实效,“以林为主”的绿化方针值得进一步深思和商榷,“一退双还”的责任制和利益机制需进一步完善等一系列问题,值得进一步深入思考和认真解决,以保证“一退双还”和国土绿化工作的持续和健康发展。     

黄土丘陵区流域主要植被类型养分循环特征

以黄土丘陵沟壑区典型小流域纸坊沟流域为例,系统研究流域在植被稳定恢复期1种乔木、4种灌木和9种草地植被类型的养分循环平衡特征。结果表明,乔灌植被类型的叶片养分含量明显高于当年的新生枝条,新生枝条则明显高于枝干;乔木植被类型的生物量、氮磷养分累积量明显高于灌木植被类型,灌木植被类型则高于草地植被类型;乔木的氮养分循环速率是0.789,灌木为0.742,草地为1.000;乔木P2O5循环速率是0.881,灌木为0.758,草地为1.000。乔木的氮养分年盈余量是333.0 kg/km2,灌木为508.5 kg/km2,草地为597.0 kg/km2;乔木的P2O5年盈余量是333.0 kg/km2,灌木为423.0 kg/km2,草地为531.0 kg/km2。